John Baymore on wed 11 jul 01
Many potters refire their iron reds in their bisque firings to make them
redder. Why do they do this?...it's because this
lets the glaze spend more time in the 1300-1800 degree range where the
crystals grow.
Another thought......
This also gives more time for the iron compounds contained in the crystal=
s
on the surface glaze layers to become oxidised..... which improves the re=
d
color.
I can get great variation in my saturated iron glazes in my noborigama,
chamber to chamber, by controlling the burn off of the coal bed in each
chamber's fireboxes on the early part of cooling.....which affects the
atmosphere in the initial cool down phase. Same glaze...... totally
different look. From tomato red by being well oxidised on cooling, to de=
ep
cordovan tessha (almost a plum toned brown) when reduced.
Of course ....... the cooling rate of my noborigama is VERY slow so there=
is time for good glaze development on cooling. About two days to "cold".=
=
This is the KEY thing to get "rich" glaze development..... even in
oxidation (I often fire chambers in oxidation...different glaze look from=
same glazes). Even non matt glazes often depend on microcrystaline stuff=
happening to develop a good "look".
Best,
.............................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop August 17-26,
2001"
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